The present invention relates to a vessel for working under water.
Sub-surface vessels which are used for observation and carrying out certain tasks under water are previously known. At depths larger than 300 m such vessels are required, since conventional diving techniques at such depths entail very time-comsuming readjustment processes for the divers and the duration of each diving operation becomes very short.
Thus, completely remote-controlled vessels for monitoring and carrying out of minor tasks under water are known. Such vessels can as a rule only be used for remote observation of certain areas and collection of samples of sea water at the depth position of the vessel or in some cases for collection of samples from the ocean bed. However, it is very difficult by means of such remote-controlled vessels to carry out, e.g., repair and installation work, since even advanced remote-controlled mechanisms cannot compensate the human sense of locality on the site. Apart from the fact that such work is very difficult to accomplish from the carrier vessel, the equipment required to carry out a remote-controlled working operation is very complicated and expensive.
Thus, there are also known sub-surface vessels, e.g., of the mini-submarine type, in which the crew is accommodated in a chamber with an atmospheric pressure therein and from this chamber controls various devices mounted on the outside of the vessel. The sojourn under water can then be made relatively comfortable for the crew compared to diving work, and it may last for periods comparable to those of ordinary sub-marine operations. Further, with such vessels the advantage is obtained that the operator can directly observe the work which is carried out and on the spot decide whether it is satisfactory.
The present invention thus relates to a vessel for working under water of the type comprising a residence chamber with an atmospheric pressure therein and accommodating the required control means for controlling devices and tools on the outside. Previously known vessels of this type are, however, encumbered with the disadvantage that a laborious and time-consuming work is required to detach the vessel if parts of the vessel or the exterior devices thereof should become hooked to the bottom or other equipment on the underwater site.
From U.S. Pat. No. 3,369,368 there is known a diving structure comprising a pair of spherical units rigidly interconnected by a common hatchway communicating the interiors thereof with each other. The structure is not connected to a service section carrying working tools and devices and primarily serves as a pressure regulating means for divers.
U.S. Pat. No. 3,527,184 teaches a manned observatory adapted for oceanographic and ocean engineering research, said observatory not being able to carry out any working operations under water.
In GB-PS No. 1,159,060 there is described a living quarter for underwater works. It is true that the living quarter can be connected to a spherical diver's bell, but the living quarter is used only as an observation chamber and no working tools and devices are arranged at the outside.
From GB-PS No. 1,367,837 there is known a spherically shaped diver's bell adapted to be attached to and released from a submerged base member. The diver's bell is used for the transportation of personnel from the surface to the base member which rests permanently at the ocean bed.
A spherical diving bell is also known from GB-PS No. 1,363,798, said bell being centered and cradled in a box-like frame of a submersible working unit by a circular array of elements consisting of utility gas bottles, buoyancy elements and cushions. Since the diving bell is encircled by the array of elements and cradled in the box-like frame, the diving bell cannot easily be detached from the submersible unit, let alone when this is operating under water. Such a sub-surface vessel will therefore constitute a trap for the persons in the diving bell if said vessel should be hooked or wedged during underwater operation. The escape path of the diving bell is blocked and only another sub-surface vessel having necessary complicated rescue means would be able to release the hooked or wedged working unit or the diving bell.